Robert Mills (1781 –1855) is most famously known for designing the Washington Monument. Mills studied in Charleston, South Carolina as a student of Irish-born architect James Hoban. He also designed the Department of Treasury building, east of the Executive Mansion (White House) and several other federal buildings in Washington, D. C. including the U.S. Patent Office Building, patterned after the Parthenon (now renovated into two adjoining museums of the Smithsonian Institution, the Smithsonian American Art Museum and the National Portrait Gallery) and the old General Post Office. In South Carolina, Mills designed county courthouses in at least 18 counties, some of the public buildings in Columbia, and a few private homes.